Bison in Trouble | God's World News
Bison in Trouble
Critter File
Posted: January 01, 2020

The clock is ticking, and bison are changing. Or maybe we should say they’re becoming less different than they used to be.

Researchers in North America gather tail-hair at bison roundups. They shoot bison with small, flesh-biting darts. Sometimes they collect blood from bison killed by hunters. All these samples give scientists a peek at bison DNA. Information from a tiny hair or drop of blood contains all of the bison’s genetic information. And what happens when scientists read the DNA? They say, “These bison have a problem.”

Wild North American bison wander in small herds. The herds are isolated from each other. When a herd is too small, not enough genetic variety exists in its gene pool. When it is isolated, new genes can’t mix in from other bison groups. This makes animals less able to fight off disease.

“Some of these herds that lost the most genetic diversity do have a high probability of going extinct,” explains Cynthia Hartway, a conservation scientist.

Bison have been in trouble before. Once, tens of millions of wild American bison existed. In the 1800s, people hunted and killed too many. Fewer than 1,000 survived.

Now U.S. government officials try to protect bison. Their programs support about 11,000 genetically pure bison. (Well—these bison are almost pure. Their genes  do show that some bison have had calves with cattle in the past. That happens sometimes when bison herds aren’t big enough.) Other groups work to save bison too.

What will help bison? People have to plan. They can exchange a few bison between herds every 10 years. That will help keep small herds from deteriorating.

But Ms. Hartway says that’s not enough. “We’re kind of putting a band-aid on the problem,” she says. In the long run, she thinks, bison must live in bigger groups.